1. Field of the Invention
The present invention relates to a system that processes and responds to messages generated by a digital data processing machine. More particularly, the invention concerns an apparatus, article of manufacture, and method for receiving both immediate-response and delayed-response messages from a data storage subsystem, selectively routing the messages to specialized expert local facilities (ELFs), performing designated functions at the ELFs, generating an appropriate output message, and transmitting the output message to the data storage subsystem. According to the invention, these messages concern the insertion of removable data storage media into a library of the data storage subsystem.
2. Description of the Related Art
Many different machines require operator supervision. Although automation is increasing, some type of management by an operator is still required for many simple machines such as drill presses, facsimile machines, and sewing machines. With more complicated machines, an operator is even more important, to perform critical and often complicated duties.
For example, most mass data storage systems require some type of operator support. Such data storage systems often store customer data on magnetic tapes, magnetic disk drives, or a combination of the two. These systems need an operator to perform error/exception handling, to backup data, to configure hardware devices, and to perform other functions. Furthermore, in storage libraries employing portable data storage units, such as tapes, operators must manage the media pool. This involves, for instance, supplying blank media, labelling tapes, advising the system when new tapes are introduced, and the like.
Thus, the operator provides the mass storage system with a number of benefits. On the other hand, use of an operator also comes with a number of drawbacks. One drawback, for example, is the cost of paying a highly trained person to monitor the data storage system. It may even be necessary to have an operator at hand twenty-four hours a day in systems that store particularly important data, such as automated teller machines, telephone directory information, internationally accessible data, and the like. In these systems, the cost of the operator can be substantial.
Another drawback of human operators is the potential for human mistakes. And, with human operators comes the possibility of human work scheduling problems. The operator's absence from the data storage system at a critical time may have serious consequences. For example, recovery from certain types of system errors may be impossible without operator intervention, thus rendering the entire storage system inoperative.
As a further example, one particularly important yet difficult operator task involves the introduction of removable media such as tape cartridges into a data storage library of a mass storage system. Many mass storage systems include tape libraries supervised by a library manager that oversees a plurality of tape cartridges and multiple tape drives. In some cases, the tape library is managed by a storage controller.
When a tape is introduced into the library, the human operator must perform the following sequence. First, the operator manually inserts the tape into an input facility, such as a slot provided in the library. Next, using a keyboard coupled to the library manager, the operator determines whether the tape has already been catalogued. Cataloguing a tape involves recording various information about the tape in a catalog, maintained by the library. Then using a keyboard coupled to the storage controller, the operator ascertains the tape's category. The operator then uses the storage controller's keyboard to catalogue the tape (if not already catalogued), and to establish an appropriate category for the tape. To complete this step, the operator must manually instruct the library to sequentially and individually load and process the cartridge. This may be time consuming, especially if multiple tape cartridges are being introduced into the library, each requiring the operators individual attention.
The need to facilitate insertion of new media into a data storage library is crucial to such mass storage systems. In this respect, the human operator performs an integral function. However, as discussed above, the use of a human operator has a number of limitations.